702 Mlt. G. E. DOBSON ON THE MOLOSSI. [Nov. 7, 



each of which, without regard to priority, has met with favour from 

 different zoologists, scarcely any two appearing to agree in adopting 

 the same term ; so that the same species is described not infrequently 

 under three or four different generic titles in the works of almost 

 contemporaneous observers. This has, no doubt, been due in a 

 great measure to the original very imperfect definitions of these 

 genera, and also to the want of any trustworthy arrangement of the 

 large number of new species subsequently described. 



The first satisfactory attempt to arrange the species scientifically 

 in a systematic form, and to determine their correct synonymy, was 

 made by Prof. Peters, who published, in 1805, in a footnote to his 

 paper on the Brazilian species of Bats described by Spix*, a short 

 list of the genera, subgenera, and typical species of this group, with 

 descriptions of a few new species, and subsequently, in the same 

 journal, gave the results of his examination of the typical specimens 

 from which Geoffroy's and Wagner's original descriptions were 

 taken. Finding, however, that not half the species of Jlolossi now 

 known are included in Prof. Peters' s list, in which also no descrip- 

 tions are given, and that much remained to be done before any thing 

 approaching a correct list of the species and their synonymy could 

 be made out, I was induced to give the subject my special attention ; 

 and the following monograph of the species is the result of my 

 examination of a large number of specimens (including most of the 

 types) preserved in the British Museum, in the museums at Leyden, 

 Berlin, and Paris, and in the Indian Museum, Calcutta, as well as in 

 several smaller collections. 



The Molossi may be defined as Bats of the family Emballonuridae 

 with short legs and well developed fibulae, with broad strong feet 

 (whereof the first toe or the first and fifth are much thicker than 

 the others) furnished with long, curved, prehensile hairs ; with a 

 thick fleshy tail produced far beyond the posterior margin of the 

 intcrfemoral membrane ; with flat broad heads, and obtuse, obliquely 

 truncated muzzles terminated by the projecting margins of the 

 nostrils ; with generally large and broad, often united ears, and a 

 short, sometimes minute, tragus ; with a single pair of well developed 

 upper incisors converging inwards and forwards. 



In all the species the upper lip is very thick, and often deeply 

 furrowed by vertical wrinkles, evidence of its great expansibility. 

 The wings are very narrow, and the middle finger very long, its 

 metacarpal bone in most species slightly exceeding the total length 

 of the last finger. The first phalanx of the middle finger is short, 

 less than half the length of the metacarpal bone, on the dorsal 

 surface of which it is folded forwards in repose. The interfemoral 

 membrane sheathes the base of the tail, and is movable at the will 

 of the animal backwards or forwards upon it, thus increasing or 

 diminishing its surface. 



The great length and narrowness of the wings indicate rapid 

 flight; and the power possessed by these Bats of varying the extent 

 of surface of the interfemoral membrane must confer upon them 

 * Monatsb. Akad. Berlin, 1805, p. 573. 



